Slack adjuster for vehicle brakes



A. B. BROLUSKA.` sLAcK AnlusTER F05 VEHICLE BRAKES.

APPLICATION FILED MAY 2.' 1921- Patented Mar. 21

the brakes.

UNITED STATES AMEL B. BROLUSKA, or DETROIT, MICHIGAN. l

SLACK ADJUSTER FORVEHICLE BRAKES.

Specication of Letters Patent. Patented Mar. 21 1922.

Application mea may 2, i921. serial No. 465,972.

ATo all whom. t may concern.

Be it known that I, AMEL B. BRoLUsKA, a citizen of the United States, residing at Detroit, in the county'of Wayne and State of Michigan, have invented a new and useful Slack Adjuster for Vehicle Brakes, of which the following is a specification.

This invention relates to slack adjusters for vehicle brakes, and more particularly for the brakes of railway cars. f

It is the object of the invention to provide an adjusting device for automatically taking up the slack in the actuating mechanism of car brakes resulting from wear of'the brake shoes upon the wheels.

In attaining this object the invention contemplates the provision of a telescopic twopart thrust bar connecting elements of the mechanism which react upon each 'other in undergoing an application and release of the brakes, so as to effect an elongation adjustment of said thrust bar when a predetermined amount of slack has resulted from wear on the brake shoes, by means of a gear and rack mechanism actuable by the excess movement to which one of the brake levers is subjected as the result of such slack.

A further feature of the invention is the provision of means to maintain the adjusted relation of the telescopic members without imposing an iuidue stress upon the automatic adj usting means.

A preferred embodiment of the invention is hereinafter described and is illustrated in the accompanying drawing, wherein,

Fig. 1 is a longitudinal vertical sectional viewv of a brake mechanism, having the improved automatic slack adjustment feature, the illustrated positions of the parts corresponding to normal of released positions of Fig. 2 is a view of the same in horizontal section. the section being taken upon line 2 2 of Fig. 1.

Fig. 3 is a side view kof an end portion of vthe thrust bar, illustrating particularly the automatic adjustment device, a portion -of the latter being in section as indicated by line 33 of Fig. 2.

Figa is a cross-sectioii view taken upon line 4-4 of Fig. 1.

In these views the reference characters 1 and 2 designate respectively the usual actuating and actuated brake levers, and 3 and 4- indicate inner and outer telescoping members which form an adjustable connection between the lower endsv of said levers, 're--y placing'the usual thrust bar. The top of the inner member 3 is formed withalongitud inal rack 5 in a. substantially central portion 4of said member and is further formed with'a channel 6 extending from Ysaid rackV to one end of saidmember. The rack 5 is engaged by a' pinion 7 housed within a central enlargement 8 of theouter .member 11, and fast upon a stub shaft 9 j ournaled in the side walls of s aid enlargement`,;as best seen ,y in Fig. 4. 4,Said stub shaft projects at one end exteriorly of said enlargementand carries a ratchet-wheel 10 fast upon saiolV shaft. Said ratchet-wheel, as may best be seen in Fig. 3, is located within al chambered rock arm 11 loose upon said shaft and projecting downwardly therefrom. Said arinis provided with a cover plate 11"for the chamber there is also pivotally mounted a pawl-12 v and a coiled springlurging said pawl into a lost motionconnection with the lever 1established by a pin 17 laterally projecting from said lever and engagingin a slot 18 transversely formed in said arm. The brake ybeam connections to the levers 1 and Q'are indicated in dash lines at 19.: Y l

AConsidering now the operation of the device, as so far described,1it will be understood by those familiar.l with the art that the actuating lever 1 is swung'to thexright fulcrum forY this movement, and the brake beam connection 19 forming a fulcrum memreceiving'said ratchet-wheel, said plate being :removably secured to the arm by any suitable means.'` lVithin .the chamber ofgthe arm 11 4. The upper extremity' of the arm 15 has Y.

k(referringto Fig. 1) in applying the brakes, Y' the npivot member 16 initially providing'a ber driving the latter Vportionof the stroke Y of the lever. While saidlever is fulcruming .upon the,y brake beamy connection the thrust bar formed by the members 3 and 4 is being shifted-to the left `(seeFig. 1) rocking the secondary lever I2 andyactuating the direction, opposite to thatpreviously imparted to the other brake beam. Prior. to any taking up of slack due to wear, the angular movement of the lever l, requisite brake; beam connected to `said lever in a Vas sirens of releasing thelatter. spring 22 `urges said detent toward the reto fully apply the brakes, does not affect the arm 15, the pin 17 carried by the lever l having merely a lost motion movement in the slot 1S of Said arm. As the bearing faces of the brake shoes (not shown) are gradually Wornaway, however, the angular travel of the lever 1in applying the brakes is correspondingly increased, and the invention utilizes this effect upon said lever to take up the slack resultingV from Wear.v Thus the` slot `18 is `so proportioned in length that a predetermined slight increase in the angular movement of the lever l will engage the in17 with the righthand extremity otpthe slot 18 (see Fig. 1) and shift the arm 15 more or less to the right as the brakes are applied. Such ac` tion of the arm'l will result in a pull being exerted through the rodlt upon the `between *the lever l and said arm, and a reverse swinging movement of the arm 11 will beeiected by the rod 14. During this reverse movement of said arm, the pawl 12 has driving engagement with the ratchet 'wheel 10, and through the latter the pinion 7 is turned in such a direction as to actuate the member 3 to the left (see Fig. 1), efecting a predetermined elongation of the members 3, 4, and thereby taking up the slack.

`In order to maintain the members 3 and 4 in their adjusted relation without unduy stressing the mechanism affecting ,their a justment "there is provided a wedge-shaped detent 20 arranged at one side of vthe mem.- bei 3 Within a correspondingly shaped housing 21 of the member 4. The engag ing faces ofsaid detent and the'inember, '3 are formed `with.verticalratchet-toothed `serrations permitting movement of the member 3 tojthe left (see` Figxvl) but resisting reverse movement of said member.

`Said idetent Wedges inthe housing 21 in resistinv movement `of said member. 3 to the" right, and may be shifted slightly 'toward the largerrend of said housing to clear the teeth of the member 3 when de- A` coiled duced end of the housing'Ql and into normal interlocking engagement fwith the ineinber 3. A hooked pin 23 secured to said datent projects freely through the larger end of the housing 21, providing for release of said detent from the member 3 in case it is desired manually to effect an adjustnient .in the length of the bar 3, f1.

lt is a feature of the described invention that the adjustment for taking up slack adjusted position of the parts 3, 4 indepen dently of the mechanism ali'ectiiigthei'r adjustment. f

` lVhat I claim'is:

l. In a slack take-up mechanism for vehicle brakes, inner and outer telesccpically" engaged members, a rack of transverse teeth longitudinally extending upon the inner of said members, a pinion engagingsaid-rack, a housing integral with the outer member,

receiving saidfpinion, a shaft'carrying said' pinion journaled in sadfhousing, an actu ating member for said shaft having a' lost motion drive connection with saidy lever establishing a drive to said-inemberifrom said lever only uponl abnormal angularv movement of the latter, a Wedge shaped serrated dentent engaging a serrated face of the inner telescopic member to maintain any adjustment thereof with relation to the outer "member, a correspondingly shaped housing integral With the outer member receiving saiddetent, and a springurging said` detent toward the-'reducedy end of said housing and intointerlocking Vengagement With said inner member.

2. In a slack take-up mechanism for vehicle brakes, a brake lever,` a! thrust baricennected thereto comprising a pair of telescopically engaged members, a rack olf-transone of said members, a pinion engaging 'said rack, a shaft journaledupon the other of said members 'carrying said 'pinion,'a ratchet ,ivheeliast upon'said shaft, an aimfpivoted ios verse teethlongitudinally extending upon drive connection ii'ron'i said lever 'toV the armA co-pivotal therewitli,`establishing a drive only upon anabno rinalfan guiar `movement of the lever, and means independent of' said paivl for maintaining ielative'adjustmeiit of' the"telescopically eng-aged members. 'u

In testimony whereof 'l sign tliisspelcilication'.

Y AMEL B. rBROLUSK.` 

